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, Miran Sra'rhs CHARLES ROBESON SQUIRE, OF BROOKLYN, NEW YORK, ASSIGNOROF ONE HALF TO JAMES F. HOTGHKISS,

OF PLAINFIELD, NEW JERSEY.

PROCESS OF PREPARING ORES FOR AMALGAMATION AND DESULPHURIZING THE SAME.

SPECIFICATION forming part of Letters Patent No. 309,168, dated December9, 1884.

Application filed July 21, 1883. Renewed August 2, 1884. (No specimens.)

1' 0 ctZZ whom it may concern.-

Be it known that 1, CHARLES RoBEsoN S UIRE, of the city, county, andState of New York, have invented certain new and useful Improvements inProcesses of Preparing Ores Containing the Precious Metals forAmalgamation and Desulphurizing the Same, of which the following is aspecification.

In carrying out my invention I use a solution of the residuum from themanufacture of nitric acid. This residuum is sometimes calledniter-cake, and its analysis is substantially as follows: sulphate ofsoda, 75.90; free sulphuric acid, 16.61; water, 6.01; insoluble matter,1.29. Total 99.81.

The strength of the solution must be determined by experience. I havewith good effects used it of about 35 Baum, subject to variation, asoccasion has required.

The solution is used upon ores that have been roasted as well as uponthose that have not; and the process consists in immersing the orcs in abath of niter-cake in solution, either alone or in the amalgamatorcontaining the mercury. If the ore, either roasted or not, is immersedin the solution, either in a bath of said solution or in an amalgamatorwith mercury, the solution has a scouring effect upon the oxide of ironand gold, by means of which the iron is removed and the gold left freeto be taken up by the mercury.

This action is partially chemical and partially due to the mechanicalaction of the pulverizer. It has been found that mercury cannot flour orfloat in amalgamating, either in this or any any other process, in thepresence of the said solution.

This process applies to all ores carrying gold or silver. 7

One of the advantages presented by nitercake, when used in solution, isin the large amount of acid present, and the cheapness of the miter-cakeas a refuse product of the manufacture of nitric acid, hitherto unusedfor this purpose, is to be considered.

I do not wish to restrict my invention to the use of the solution at anyparticular stage of the operation upon the ore, or any particularcharacter of operation thereon, whether such operation involves the useof fire, steam, or any other agent, or Whether the solution is used withor without heat, or whether the ores are pulverized or not. Neither do Iwish to confine my invention to the accomplishment of any one particulareffect upon the ore or metals, as from what has been said hereinbeforeits effects thereon when differently applied, or under differentcircumstances and conditions, are seen to be various-as to desulphurizethe ores, prepare the metals for amalgamation, prevent the fiouring orsickening of the quicksilver, 8w.

1 am aware that ores have been reduced by calcination with sodicsulphate. Neither do I claim the use of a solution of salt-cake alone,as set forth in my application filed July 21, 1883, Serial No. 101,520,nor that of a solution of a mixture of salt-cake and miter-cake, as

set forth in my application filed April 10, 1883, Serial No. 91,305; butI am not aware that ore, whether roasted or not, has been desulphurizedand prepared for amalgamation by exposure to the action of niter'cakemaintained in a state of solution.

Having thus described my invention, I claim 1. The within-describedprocess of preparing ores for amalgamation, which consists in subjectingthe ore to a solution of niter-cake, substantially as herein set forth.

2. The within-described process of desulphurizing ores, which consistsin subjecting them to a solution of niter-cake, substantially ashereinbefore set forth.

In testimony whereof I have hereunto set my hand and seal this 19th dayof July, A. D. 1883.

WVitnesses:

SAMUEL P. BELL, W. S. MIDDLEroN.

